use std::{env, fs};
use std::error::Error;

pub struct Config {
    query: String,
    file_path: String,
    ignore_case: bool,
}
impl Config {
    pub fn build(mut args: impl Iterator<Item=String>) -> Result<Config, &'static str> {
        // if args.len() < 3 {
        //     return Err("参数异常");
        // }
        args.next();
        let query = match args.next() {
            Some(arg) => arg,
            None => return Err("参数异常"),
        };
        let file_path = match args.next() {
            Some(arg) => arg,
            None => return Err("参数异常"),
        };
        let ignore_case = env::var("IGNORE_CASE") == Ok("1".to_string());
        Ok(Config { query, file_path, ignore_case })
    }
}
pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(config.file_path)?;
    let results = if config.ignore_case {
        search_case_insensitive(&config.query, &contents)
    } else {
        search(&config.query, &contents)
    };
    dbg!("{}",results);
    // for line in results {
    //     println!("{line}");
    // }
    Ok(())
}


#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn case_sensitive() {
        let query = "duct";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.";
        assert_eq!(vec!["safe, fast, productive."], search(query, contents));
    }


    #[test]
    fn case_insensitive() {
        let query = "rUst";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.
Trust me.";
        assert_eq!(vec!["Rust:", "Trust me."], search_case_insensitive(query, contents))
    }
}
pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    contents
        .lines()
        .filter(|line| line.contains(query))
        .collect()
}

pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    // let mut results = Vec::new();
    // let query = query.to_lowercase();
    // for line in contents.lines() {
    //     if line.to_lowercase().contains(&query) {
    //         results.push(line);
    //     }
    // }
    // results
    let query = query.to_lowercase();
    contents
        .lines()
        .filter(|line| line.to_lowercase().contains(&query))
        .collect()
}
